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Posts Made By: Paul Leuba

November 12, 2007 07:30 PM Forum: Telescope Making

Can you help me identify this lever thingy?

Posted By Paul Leuba
Doug Walton said:
My question: what are these called, and where can I get them (or something like or, maybe better?)? It would be great if I could get one or two with some kind of adjustable-length connecting rod to go with it.

Doug,

Do you happen to have a picture of the inside of the focker box? I am wondering exactlyhow this clamp/lever attached to the rod that controils the Azimuth bearing.

Thanks digging this pic out and posting.

March 12, 2008 03:21 PM Forum: Telescope Making

Can you help me identify this lever thingy?

Posted By Paul Leuba
Doug Walton said:

Hi everyone,

I've attached an image that shows a red-handled lever on the side of a dob rocker box. I believe the way it works is like a lever "switch" - when the level is push all the way to the left, it pulls on a rod on the inside of the rocker box, and when moved all the way to the right, it pushes the rod back in the other direction. I also think it sorta locks in place at either end of its throw. It functions as an azimuth drive engage/disengage lever.

Doug


Hi Doug,

Not sure if you still own your StarMaster, but I just implemented a design that would bring the Azimuth adjustment lever to the outside of the rocker box. I have attached a picture...

See the thread I started here in the StarMaster Forum for more pictures.

http://tinyurl.com/ysj9hd



March 28, 2008 03:38 PM Forum: Refractors

102FL rear fluorite lens

Posted By Paul Leuba
John Powers said:

I recently acquired a mint condition Vixen 102FL. I love this thing!

These telescopes have been imported into the United States at least since the mid 1980's. I have owned four samples of the Vixen Fluorite two branded by Orion and two of them were the Celestron version. Late last year I fully restored a C102F originally manufactured in 1990. The OTA was in very poor cosmetic shape and the lens was dirty. I cleaned the rear, uncoated, Fluorite element. Using common sense techniques and advice from Rolando, the lens turned out perfect.

I think the Vixen Fluorites are remarkable visual telescopes and are amazing bargains on today's used market.

June 5, 2008 07:36 PM Forum: Pictures of Me and My Telescope and........

Mobile Star Base

Posted By Paul Leuba
Louis Scott Busby said:

Here's my usual setup up at Milam Gap, Skyline Drive, NVA grin

Is that a G11? What tripod are you using to support it?

Thanks.

August 7, 2008 08:05 PM Forum: Equipment Talk

Powermate vs TV Barlow ?

Posted By Paul Leuba
John Meiners said:

Besides the additional $90 for a Powermate, I was wondering if the visual enhancement is worth the added expense.. thank you, John Meiners


I think it really depends on the application. I have owned several of each. In my tests in an indoor artificial star/collimated beam setup as well as outside in the field, the Barlow is sharper on axis then the equivalent PowerMate. Subtle but noticeable.

The big selling point for the PowerMate is a non vignetting field. They're very popular with the webcam planetary imagers. But for visual, I think your better off with a plain ol' Barlow. At least this is what I've seen repeatedly in my tests.

My current favorite is a TeleVue 3X Barlow. But the AP BarCon is really nice too.

August 18, 2008 02:33 PM Forum: Takahashi

FS 152 - New Focuser

Posted By Paul Leuba
Paul Leuba said:

Here is a picture of my FS152 with new 3" FeatherTouch focuser.

A close up of the focuser...

January 26, 2009 06:36 PM Forum: Eyepieces

TV Powermate?

Posted By Paul Leuba

So I was thinking today of looking for a shorter FL eyepiece, or a 2X Powermate.


Steve,

I am going to take a slightly contrarian point of view regarding the Powermates. A year or so back, I compared a couple of the TV 2X PowerMates to several 2X Barlows.

The conclusion I came away with was that the PowerMates added some slight Spherical Aberration to the star test image. The plain TeleVue Barlow did not seem to add any aberrations that I could detect. This was on artificial star in a controlled environment as well as on Vega outside. The telescope was a very fine Vixen Fluorite.

The difference was noticeable in the star test, but did not seem to make a material difference on Jupiter.

The PowerMates are useful for the webcam/astrophoto crowd as there is no vignetting. But visually, I would tend to stick with a shorter focal length ocular, simple TeleVue Barlow or use the Nagler 3-6 zoom. The Nagler zoom adds no SA to the image whatsoever.

April 30, 2009 01:56 PM Forum: Refractors

TOA 150 claims, could this be?

Posted By Paul Leuba
Jerry Wise said:

"Orthoscopic means perfected visually and Apochromatic means you're free from those strange violet glows which often accompany bright stars or planets. Thanks to the ingenious design of layering an FPL-53 Extra-low Dispersion glass element between two extreme quality crown and flint elements - perfection ensues. And what's more, it's air spaced, so there's no oil between the elements to leak or become opaque with age. The lens cells are durably constructed to withstand transport - yet are fully able to be collimated should the owner wish to make adjustments. With 1/12th wave accuracy and an airy-disc Strehl ratio of 0.992, the optics on the Takahashi TOA-150F Ortho-APO are as near to perfection as you can get!"


I have no first hand knowledge of the design other then samples of the telescope that I have compared to my FS152. But it sounds like OPT is quoting theoretical correction. As is often done in ad copy, the marketing guys will quote the best case theoretical correction spit out by Zemax or Oslo if the design is executed flawlessly. In practice, the design is NEVER executed perfectly. There are too many variables, outside of the opticians control like glass melt, coatings etc. Variations in glass melt can be dealt with by hand figuring, but I am not sure TAK does this.

The TOA's I have seen at Cherry Springs, are really color free with a huge air gap. However, I don't believe they are corrected to a 1/12 wave.

June 1, 2009 06:43 PM Forum: ASTRONOMY

Public Observing at the ASH Naylor Observatory

Posted By Paul Leuba
Dave Mitsky said:

Weekly Sunday night public observing sessions for the summer of 2009 begin June 7 at the Astronomical Society of Harrisburg's Naylor Observatory.

Dave,

I would be interested in coming up for one of these. Do you have room and allow the public to setup their own telescopes? As you know I am not a member of ASH. The York County club I belong to, does not have many observers.

I would be interested in brining a refractor or one of my StarMasters or a Portaball etc.

Thanks.

August 26, 2009 05:58 PM Forum: Eyepieces

Best choice?

Posted By Paul Leuba
Robert Howe said:

Any thoughts on the best EP for planetary viewing with a large apo? Something in the 5 to 8 mm range. I have a Nagler 9 which is awesome. An Ethos 8 gives too much FOV, it is distracting at this magnification.

Televue Radian?
Pentax?

Cheers

Robert Howe

Hi Robert,

I agree with you on the Ethos - no need for the hyper-wide FOV and it is quite distracting. And, definitely not the Radian unless you absolutely need the eye relief.

My daily driver eyepiece set is the Type 6 Naglers. These are very comfortable and do everything fairly well. However, a few years back I obtained a set of Takahashi LE's on a whim and have really enjoyed the views they have provided in my scopes which included an FS152, a TEC160ED and a 14.5" Starmaster.

The NT6's are sharp across the FOV, but the TAK LE's are more color neutral. The LE's are also VERY sharp on axis, very comfortable and seem to offer slightly better throughput then the more complex Naglers.

The TAK LE's are the best I've used for planets without getting into the boutique eyepieces like the TMB SuperMono, AP SPL, Ziess Abbe, Pentax SMC etc.

One final thought - if you like the 9mm Nagler T6, the 7mm and 5mm offer more of the same and get quite a bit of use in a Portaball-8.

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